Growing energy crops on marginal lands, such as highway right of way (ROW), provides a potential solution to utilizing second-generation bioenergy while avoiding conflicts by occupying arable farmlands. Considering the scattered distribution of ROW lands, successful management of biomass production supply chain is a key challenge when developing a viable system at the state level. The overall objective of this study is to evaluate the feasibility of growing energy crops along Illinois highways and provide decision support to the stakeholder. To collect the system inputs, geospatial information system (GIS) and remotely sensed satellite images were employed to identify the eligible lands, and the Google Maps API was used to generate distance matrices; linear programming and mix-integer linear programming models were developed to optimize the facility selections and biomass flow patterns in different scenarios.
ROW biomass is shown to be economically feasible as an alternative fuel for heating local county facilities of the Department of Transportation. At the state level, using ROW biomass for co-firing is not economically competitive, at the cost of 2.71 cent/kWh electricity, compared to the current cost of coal used in the same power plants. Proximity of ROW biomass to the power plants has a great influence on the cost, and most of the eligible power plants locate around Central Illinois. When corn stover, another inexpensive and more abundant biomass is added to the supply chain, ROW biomass shrinks its sourcing area to reduce the transportation costs, in order to compete with corn stover. When the energy demand is expanded to fulfill the Illinois Renewable Standard (2025), the supply shortage of ROW biomass makes it a much smaller portion in the feedstock, compared to corn stover. The sourcing cites of ROW biomass are kept almost the same, while more counties are selected to supply corn stover, raising the average cost from 2.58 to 3.31 cent/kWh electricity for corn stover. Uncertainty analysis using global sensitivity indices reveals that the retrofitting capital cost is the most impactful input on the results and energy demand being the second, while transportation costs have almost no influence.
The results of this study provided a system level insight of the strategic challenges on growing energy crops along Illinois highway ROW. The model developed here is expandable with additional system inputs to accommodate more complicated scenarios. The methods and analysis documented in this study, though focused on Illinois, can also be applied to other states.